Upstream bandwidth conditioning device

ABSTRACT

A device may be used for conditioning an upstream bandwidth. The device includes a return path extending at least a portion of a distance between a supplier side connector and a user side connector, and a coupler connected within the return path, the coupler providing a secondary path. A detection circuit is connected electrically downstream the coupler, and a level detector is connected electrically downstream the detection circuit. A microprocessor is connected electrically downstream the level detector. The microprocessor includes a first buffer and a second buffer. A variable signal level adjustment device is connected within the return path electrically upstream from the coupler. The variable signal level adjustment device is controlled by the microprocessor.

FIELD OF THE INVENTION

The present invention relates generally to signal conditioning devicesfor use in community antenna television (“CATV”) systems, and inparticular to signal conditioning devices that increase thesignal-to-noise ratio of an upstream bandwidth in a CATV system.

BACKGROUND OF THE INVENTION

The use of a CATV system to provide internet, voice over internetprotocol (“VOIP”) telephone, television, security, and music services iswell known in the art. In providing these services, a downstreambandwidth (i.e., radio frequency (“RF”) signals, digital signals, and/oroptical signals) is passed from a supplier of the services to a user,and an upstream bandwidth (i.e., radio frequency (“RF”) signals, digitalsignals, and/or optical signals) is passed from the user to thesupplier. For much of the distance between the supplier and the user,the downstream bandwidth and the upstream bandwidth make up a totalbandwidth that is passed via a signal transmission line, such as acoaxial cable. The downstream bandwidth is, for example, signals thatare relatively higher in frequency within the total bandwidth of theCATV system while the upstream bandwidth is, for example, signals thatare relatively lower in frequency.

Traditionally, the CATV system includes a head end facility, where thedownstream bandwidth is initiated into a main CATV distribution system,which typically includes a plurality of trunk lines, each serving atleast one local distribution network. In turn, the downstream bandwidthis passed to a relatively small number (e.g., approximately 100 to 500)of users associated with a particular local distribution network.Devices, such as high-pass filters, are positioned at various pointswithin the CATV system to ensure the orderly flow of downstreambandwidth from the head end facility, through the trunk lines, throughthe local distribution networks, and ultimately to the users.

In stark contrast to the orderly flow of the downstream bandwidth, theupstream bandwidth passing through each of the local distributionnetworks is a compilation of an upstream bandwidth generated within apremise of each user that is connected to the particular distributionnetwork. The upstream bandwidth generated within each premise includesdesirable upstream information signals from a modem, desirable upstreaminformation signals from a set-top-box, other desirable signals, andundesirable interference signals, such as noise or other spurioussignals. Many generators of such undesirable interference signals areelectrical devices that inadvertently generate electrical signals as aresult of their operation. These devices include vacuum cleaners,electric motors, household transformers, welders, and many otherhousehold electrical devices. Many other generators of such undesirableinterference signals include devices that intentionally create RFsignals as part of their operation. These devices include wireless hometelephones, cellular telephones, wireless internet devices, citizensband (“CB”) radios, personal communication devices, etc. While the RFsignals generated by these latter devices are desirable for theirintended purposes, these signals will conflict with the desirableupstream information signals if they are allowed to enter the CATVsystem.

Undesirable interference signals, whether they are inadvertentlygenerated electrical signals or intentionally created RF signals, may beallowed to enter the CATV system, typically through an unterminatedport, an improperly functioning device, a damaged coaxial cable, and/ora damaged splitter. As mentioned above, the downstream/upstreambandwidth is passed through coaxial cables for most of the distancebetween the user and the head end. This coaxial cable is intentionallyshielded from undesirable interference signals by a conductive layerpositioned radially outward from a center conductor and positionedcoaxially with the center conductor. Similarly, devices connected to thecoaxial cable typically provide shielding from undesirable interferencesignals. However, when there is no coaxial cable or no device connectedto a port the center conductor is exposed to any undesirableinterference signals and will function like a small antenna to gatherthose undesirable interference signals. Similarly, a coaxial cable ordevice having damaged or malfunctioning shielding may also gatherundesirable interference signals.

In light of the forgoing, it should be clear that there is an inherent,system-wide flaw that leaves the upstream bandwidth open and easilyimpacted by any single user. For example, while the downstream bandwidthis constantly monitored and serviced by skilled network engineers, theupstream bandwidth is maintained by the user without the skill orknowledge required to reduce the creation and passage of interferencesignals into the upstream bandwidth. This issue is further compounded bythe number of users connected together within a particular distributionnetwork, especially knowing that one user can easily impact all of theother users.

Attempts at improving an overall signal quality of the upstreambandwidth have not been successful using traditional methods. A measureof the overall signal quality includes such components as signalstrength and signal-to-noise ratio (i.e., a ratio of the desirableinformation signals to undesirable interference signals). Traditionally,increasing the strength of the downstream bandwidth has beenaccomplished by drop amplifiers employed in or near a particular user'spremise. The success of these drop amplifiers is largely due to the factthat there are very low levels of undesirable interference signalspresent in the downstream bandwidth for the reasons explained more fullyabove. The inherent presence of the undesirable interference signals inthe upstream bandwidth generated by each user has typically precludedthe use of these typical, drop amplifiers to amplify the upstreambandwidth, because the undesirable interference signals are amplified bythe same amount as the desirable information signals. Accordingly, thesignal-to-noise ratio remains nearly constant, or worse, such that theoverall signal quality of the upstream bandwidth is not increased whensuch a typical, drop amplifier is implemented.

For at least the forgoing reasons, a need is apparent for a device,which can increase the overall quality of the upstream bandwidth thatincludes increasing the signal strength and increasing thesignal-to-noise ratio.

SUMMARY OF THE INVENTION

The present invention helps to reduce the effect of undesirableinterference signals that are unknowingly injected into the main signaldistribution system, through the upstream bandwidth, by a user.

In accordance with one embodiment of the present invention, a device maybe used for conditioning an upstream bandwidth. The device includes areturn path extending at least a portion of a distance between asupplier side connector and a user side connector, and a couplerconnected within the return path, the coupler providing a secondarypath. A detection circuit is connected electrically downstream thecoupler, and a level detector is connected electrically downstream thedetection circuit. A microprocessor is connected electrically downstreamthe level detector. The microprocessor includes a first buffer and asecond buffer. A variable signal level adjustment device is connectedwithin the return path electrically upstream from the coupler. Thevariable signal level adjustment device is controlled by themicroprocessor.

In accordance with another embodiment of the present invention, a methodis provided for conditioning an upstream bandwidth. The method includesconverting a frequency dependent voltage stream into a time dependentvoltage stream including periods of increased voltage, and amplifyingand maintaining the periods of increased voltages using a low passamplifier and a peak detector. The method further includes recording apeak value from a plurality of voltage series from within the outputvoltage stream, each series beginning with a measured voltage levelexceeding a high voltage threshold and ending with a measured voltagelevel passing below a low voltage threshold. The method further includesplacing the peak values in a first buffer, and periodically calculatinga first buffer average. The method further includes placing the each ofthe first buffer averages into a second buffer, and determining whetherthe first buffer average is one of above and below a value range, thevalue range being one of the first buffer averages placed in the secondbuffer plus (+) an upper variance amount and minus (−) a lower variance.The method further includes adding an increment of attenuation to theupstream bandwidth when the first buffer is greater than the valuerange, and reducing an increment of attenuation to the upstreambandwidth when the first buffer is less than the value range.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the invention,references should be made to the following detailed description of apreferred mode of practicing the invention, read in connection with theaccompanying drawings in which:

FIG. 1 is a graphical representation of a CATV system arranged inaccordance with an embodiment of the present invention;

FIG. 2 is a graphical representation of a user's premise arranged inaccordance with an embodiment of the present invention;

FIG. 3 is a circuit diagram representing a conditioning device includingan upstream section made in accordance with another embodiment of thepresent invention;

FIG. 4 is a circuit diagram representing a coupler used in aconditioning device made in accordance with one embodiment of thepresent invention;

FIG. 5 is a circuit diagram representing a high pass filter used in aconditioning device made in accordance with one embodiment of thepresent invention;

FIG. 6 is a circuit diagram representing a RF detection circuit used ina conditioning device made in accordance with one embodiment of thepresent invention;

FIG. 7 is a circuit diagram representing a level detector used in aconditioning device made in accordance with one embodiment of thepresent invention;

FIG. 8 is a graphical representation of a voltage stream passing from aRF detector to a low-pass amplifier within a RF detection circuit usedin a conditioning device made in accordance with one embodiment of thepresent invention;

FIG. 9 is a graphical representation of a voltage stream passing from alow-pass amplifier within a RF detection circuit to a level detectorused in a conditioning device made in accordance with one embodiment ofthe present invention;

FIG. 10 is a graphical representation of a voltage stream passing from alevel detector to a non-linear amplifier used in a conditioning devicemade in accordance with one embodiment of the present invention;

FIG. 11 is a circuit diagram of a non-linear amplifier used in aconditioning device made in accordance with one embodiment of thepresent invention;

FIG. 12 is a graphical representation of a theoretical response of anon-linear amplifier in response to a linearly increasing voltage;

FIG. 13 is a graphical representation of a voltage stream passing from anon-linear amplifier to a microprocessor used in a conditioning devicemade in accordance with one embodiment of the present invention; and

FIG. 14 is a flow chart representing a signal level measurement routineperformed by a microprocessor used in a conditioning device made inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a CATV system typically includes a supplier 20 thattransmits a downstream bandwidth, such as RF signals, digital signals,and/or optical signals, to a user through a main distribution system 30and receives an upstream bandwidth, such as RF signals, digital signals,and/or optical signals, from a user through the same main signaldistribution system 30. A tap 90 is located at the main signaldistribution system 30 to allow for the passage of thedownstream/upstream bandwidth from/to the main signal distributionsystem 30. A drop transmission line 120 is then used to connect the tap90 to a house 10, 60 an apartment building 50, 70, a coffee shop 80, andso on. As shown in FIG. 1, an upstream bandwidth conditioning device 100of the present invention may be connected in series between the droptransmission line 120 and a user's premise distribution system 130.

Referring still to FIG. 1, it should be understood that the upstreambandwidth conditioning device 100 can be placed at any location betweenthe tap 90 and the user's premise distribution system 130. This locationcan be conveniently located within the premise (e.g., the house 10, theapartment building 70, etc.), or proximate to the premise (e.g., thehouse 60, the apartment building 50, etc.). It should be understood thatthe upstream bandwidth conditioning device 100 can be placed at anylocation, such as the coffee shop 80 or other business, where CATVservices, including internet services, VOIP services, or otherunidirectional/bidirectional services are being used.

As shown in FIG. 2, the user's premise distribution system 130 may besplit using a splitter 190 so that downstream/upstream bandwidth canpass to/from a television 150 and a modem 140 in accordance withpractices well known in the art. The modem 140 may include VOIPcapabilities affording telephone 170 services and may include a routeraffording internet services to a desktop computer 160 and a laptopcomputer 180, for example.

Additionally, it is common practice to provide a set-top box (“STB”) ora set-top unit (“STU”) for use directly with the television 150. For thesake of clarity, however, there is no representation of a STB or a STUincluded in FIG. 2. The STB and STU are mentioned here in light of thefact that many models utilize the upstream bandwidth to transmitinformation relating to “pay-per-view” purchases, billing, utilization,and other user interactions, all of which may require information to besent from the STB or STU to the supplier 20. Accordingly, it should beunderstood that even though FIG. 2 explicitly shows that there is onlyone upstream bandwidth conditioning device 100 used for one premisedevice (i.e., the modem 140), each upstream bandwidth conditioningdevice 100 may be used with two or more premise devices (e.g., a modem,a STB, a STU, and/or a dedicated VOIP server) that transmit desirableupstream information signals via the upstream bandwidth.

The term “premise device” is used throughout to describe any one or moreof a variety of devices that generate desirable portions of an upstreambandwidth. More specifically, the term premise device is used todescribe devices located on or proximate to a user's premise that eitherreceive the downstream bandwidth, transmit information toward thesupplier 20 via the upstream bandwidth, or both. These premise devicesinclude internet access modems, STBs, STUs, televisions, premisesecurity monitoring devices, and any future devices that may have a needto report or otherwise provide information via the upstream bandwidth.

Further, while not shown explicitly in FIG. 2, there may be two (ormore) upstream bandwidth conditioning devices 100 located within orproximate to a single premise. For example, there may be an upstreambandwidth conditioning device 100 located between the modem 140 and thesplitter 190 and another upstream bandwidth conditioning device 100located between an STB or STU on the television 150 and the splitter190. Similarly, there may be an upstream bandwidth conditioning device100 located at any point in the premise distribution system 130 where anupstream bandwidth is being passed (e.g., from a modem, a STB, a STU, aVOIP server, etc.).

Further, while not shown explicitly in FIG. 2, there may by one upstreambandwidth conditioning device 100 located proximate to two user premiseswhen there is one drop transmission line 120 used to connect the tap 90to both of the two user premises. Even though such an arrangement is notconsidered ideal, because the upstream bandwidth from two users may bemerged prior to being conditioned, such an arrangement may be necessarywhen the two premises are located too closely to one another for thephysical placement of separate upstream bandwidth conditioning devices100.

It should be understood that the goal of placing the upstream signalconditioning device 100 into one of the locations described above is toincrease the overall quality of the upstream bandwidth in the maindistribution system 30 by increasing the signal-to-noise ratio of theupstream bandwidth leaving the user's premise before that particularuser's upstream bandwidth is merged with those of other users. Asdiscussed above, merely amplifying the upstream bandwidth fails toachieve the desired result because the undesirable interference signalspresent in the upstream bandwidth are also amplified.

Referring now to FIG. 3, the description of the upstream bandwidthconditioning device 100 will be broken down into two general topics ofdiscussion, general components and an upstream bandwidth conditioningsection 105 (“upstream section 105”). The general components will bediscussed first to develop the terminology used throughout and to helpexplain how the upstream bandwidth is passed to the upstream section105. The hardware, the operation, and the control of the upstreamsection 105 will be discussed thereafter.

Referring still to FIG. 3, the upstream bandwidth conditioning device100 may include a user side connector 210 and a supplier side connector215. Each of these connectors 210, 215 may be any of the connectors usedin the art for connecting a signal cable to a device. For example, eachof the user side connector 210 and the supplier side connector 215 maybe a traditional female “F-type” connector.

A user side surge protector 220 and a supplier side surge protector 225may be provided electrically adjacent the user side connector 210 andthe supplier side connector 215, respectively. This positioning of thesurge protectors 220, 225 allows for the protection of electricallyfragile components (discussed more fully below) positioned between thesurge protectors 220, 225. Each of the user side surge protector 220 andthe supplier side surge protector 225 may be any of the surge protectorsknown in the art for electronic applications.

A user side switch 250 and a supplier side switch 255 each have twopositions. In a first, default position (shown in FIG. 3), the switches250, 255 pass signals through a bypass path 230. In a second position,the user side switch 250 and the supplier side switch 255 electricallyconnect the user side connector 210 to a user side main path 240 and thesupplier side connector 215 to the a supplier side main path 242,respectively. As will be discussed further below, the primary componentsof the upstream bandwidth conditioning device 100 are electricallyconnected in series between the user side main path 240 and the supplierside main path 242.

The switches 250, 255 allow the total bandwidth to pass through thebypass path 230 in the event of a fault within the upstream bandwidthconditioning device 100, such as an electrical power failure. Theswitches 250, 255 may be any of the SPDT (Single Pole Double Throw)switches known in the art. For example the switches 250, 255 may beselected and installed such that when there is no electrical powerpresent to the upstream bandwidth conditioning device 100, the switches250, 255 automatically select the first, default position to pass thetotal bandwidth through the bypass path 230. Conversely, when there iselectrical power present, the switches 250, 255 move toward their secondposition passing the total bandwidth to the main paths 240, 242. In theevent of an electrical short within the upstream bandwidth conditioningdevice 100, it is likely that the short will cause an additional currentflow that will ultimately result in the destruction of a fuse or in anopening of a circuit breaker type device (not shown). Accordingly, sucha short will likely result in a loss of power to switches allowing thetotal bandwidth to pass through the bypass path 230.

A microprocessor 310 (discussed more fully below) may also be used toactuate the switches 250, 255 to their first position (i.e., to thebypass path 230) when a fault, other than an electrical power loss, isdetected within the upstream bandwidth conditioning device 100. Whilethe circuitry for such a connection is not shown in FIG. 3, it should beunderstood that the control by the microprocessor 310 should be inaddition to the switches 250, 255 automatic positioning due to anelectrical failure.

The term “microprocessor” used throughout should be understood toinclude all active circuits capable of performing the functionsdiscussed herein. For example, the microprocessor 310 may be replacedwith a microcontroller, a system specific digital controller, or acomplex analog circuit.

The bypass path 230 may be a coaxial cable, an unshielded wire, and/or ametallic trace on a circuit board. All of these options are capable ofpassing the total bandwidth with little signal attenuation.

A user side diplexer 260 and a supplier side diplexer 265 areelectrically coupled to the user side main path 240 and the supplierside main path 242, respectfully. The diplexers 260, 265 are arrangedand configured to create a forward path 244 and a return path 246, 248there between. Each of the diplexers 260, 265 may function like acombination of a splitter, a high-pass filter, and a low-pass filter,the splitter dividing the respective main path 240, 242 into two signalpaths, one for each of the low-pass filter and the high-pass filter.Using the terms of this combination, each of the high-pass filterspasses the downstream bandwidth, and each of the low-pass filters passesthe upstream bandwidth. In the present example, the downstream bandwidthpasses along the forward path 244 between the diplexers 260, 265. Ofparticular importance to the present upstream bandwidth conditioningdevice 100, the upstream bandwidth passes along the return path 246, 248between the diplexers 260, 265. The remainder of the description belowfocuses on the hardware, the operation, and the control of the upstreamsection 105 attached within the return path 246, 248.

In an effort to set the stage for the following discussion, thehardware, the operation, and the control of the upstream section 105will be first described here in very general detail. The upstreamsection 105 selectively attenuates the upstream bandwidth in incrementswith the knowledge that a typical premise device will increase the powerwith which it transmits its portion of the upstream bandwidth (i.e., thedesirable upstream bandwidth) to account for the added attenuation. Theresult is that the desirable upstream bandwidth will be larger inpercentage than the remaining portions (i.e., the undesirable upstreambandwidth). To accomplish these goals, the upstream section 105 must beable to precisely measure the level of the desirable upstream bandwidthin order to increase the amount of attenuation without adding moreattenuation than the premise device can account for in terms ofincreasing its output power. Precise measurements of the desirableupstream bandwidth level are difficult, if not impossible, to make usingonly traditional level detectors.

The desirable upstream bandwidth is difficult to measure due to theinherent functional characteristics of premise devices. For example, apremise device typically transmits a desirable upstream bandwidth onlywhen that premise device is being requested to transmit information. Forexample, a premise device, such as an internet access modem, typicallytransmits information only when a user sends information to theinternet. Because there is no way to anticipate when such information isto be sent, the desirable upstream bandwidth created by the premisedevice must be assumed to be time independent and time discontinuous.Further, the continuity of the information that is being transmittedvaries greatly, such as between a simple Pay-Per-View purchase requestand an Internet upload of a large, detailed photograph. In other words,the portion of the upstream bandwidth created by a premise device mayoccur at any time and may occur for any length of time. The upstreamsection 105 includes features that are used specifically to identifythis time independent and time discontinuous desirable upstreambandwidth.

The upstream section 105 includes a coupler 340 connected within thereturn path 246, 248 to pass a portion of the upstream bandwidth, interms of power and/or frequency range, to subsequent devices in theupstream section 105 via secondary path proceeding from a coupler output342 (FIG. 4). One skilled in the art would readily understand, based onthe present description and the size requirement of a particularinstallation, which type of coupler would be suitable for the presentpurpose. For example, a simple resistor, a power divider, a directionalcoupler, and/or a splitter may be used with careful consideration of theeffects that these alternatives may have on the characteristic impedanceof the upstream bandwidth conditioning device 100. Individual componentspresent in one embodiment of the coupler 340 are represented in FIG. 4.

The term “connected” is used throughout to mean optically orelectrically positioned such that current, voltages, and/or light arepassed between the connected components. It should be understood thatthe term “connected” does not exclude the possibility of interveningcomponents or devices between the connected components. For example, thecoupler 340 is connected to a RF amplifier 365 even though a high passfilter 350 is shown to be positioned in an intervening relation betweenthe coupler 340 and the RF amplifier.

The terms “connected electrically downstream” and “connectedelectrically upstream” may also be used throughout to aid in thedescription regarding where or how the two components are connected. Asan example, when a second device is connected electrically downstreamfrom a first device, the second device receives signal from the firstdevice. This same arrangement could also be described as having thefirst device connected electrically upstream from the second device.

Referring back to FIG. 3, the high-pass filter 350 is connectedelectrically downstream from the coupler 340 such that the coupleroutput 342 is electrically connected to a high-pass filter input 352(FIG. 5). The high-pass filter 350 is utilized in this instance to passonly a segment of the upstream bandwidth through to the remainingdevices, discussed below, via a high-pass filter output 354 (FIG. 5).Such a high-pass filter 350 may not be required in all instances, butmay be beneficial in that it attenuates segments of the upstreambandwidth that are known not to carry the desirable upstream bandwidth.For example, if the premise devices are known to provide their desirableupstream bandwidth in a specific segment of the upstream bandwidth, itmay be beneficial to configure the high-pass filter 350 to attenuatesegments of the upstream bandwidth below the specific segment of theupstream bandwidth where the premise device transmits. One skilled inthe art would readily understand, based on the present description andthe size requirements of a particular installation, which type ofhigh-pass filter would be suitable for the present purpose. Individualcomponents present in one embodiment of the high-pass filter 350 arerepresented in FIG. 5.

A RF detection circuit 360 is connected electrically downstream from thehigh-pass filter 350 such that the high-pass filter output 354 iselectrically connected to a RF detector input 362 (FIG. 6). The RFdetection circuit 360 includes a RF amplifier 365 a RF detector 366 anda low-pass amplifier 367. The RF amplifier 365 amplifies the portion ofthe downstream bandwidth passed through the high-pass filter 350 inpreparation for the RF detector 366. The RF detector 366 functions as aninverse Laplace transform, the Laplace transform being a widely usedintegral transform, to convert the portion of the downstream bandwidthfrom a frequency domain voltage stream into a time domain voltagestream. The inverse Laplace transform is a complex integral, which isknown by various names, the Bromwich integral, the Fourier-Mellinintegral, and Mellin's inverse formula. An alternative formula for theinverse Laplace transform is given by Post's inversion formula. The timedomain voltage stream is then passed to the low-pass amplifier 367,which amplifies the voltages while discriminating in the time betweenthose having suitable signal duration and those that are to short forusage within the following circuitry stages.

As an example, FIG. 8 represents a time domain voltage stream output 400from the RF detector 366 to the low-pass amplifier 367. The time domainvoltage stream 400 includes increased voltage levels 410 and 420 thatlast for varying amounts of time. Longer sections of increased voltage410 typically represent significant information being sent by a premisedevice, while shorter sections of increased voltage 420 typicallyrepresent “pings,” which are very short bursts of little information.These longer sections of increased voltage have a period that may betypical for a particular premise device. In other words, the longersections of increased voltages 410 may have shorter or longer sectionsof lower voltage between the longer sections of increased voltages 410.This period, which may change based on the types of premise devicespresent, will be important when discussing a level detector 370.

Referring now to FIG. 9, the low-pass amplifier 367 creates a voltagestream 402 where the longer periods of increased voltage 410 (FIG. 8)result in higher voltages 412 and where the shorter periods of increasedvoltage 420 (FIG. 8) result in lower voltages 422. This voltage stream402 is then output to the level detector 370 from a RF detection circuitoutput 364. One skilled in the art would readily understand, based onthe present description and the size requirements of a particularinstallation, which type of components should be used to create the RFdetection circuit 360. Individual components present in one embodimentof the RF detection circuit 360 are represented in FIG. 6.

The level detector 370 is connected electrically downstream from the RFdetection circuit 360 such that the output of the RF detection circuitis electrically connected to a level detector input 372 (FIG. 7). Thelevel detector 370 generates additional current based on the voltagestream provided by the RF detection circuit 360, and the level detector370 includes at least one diode and at least one relatively largecapacitor 376 to store the current provided. A voltage stream 404 (FIG.10) provided from the large capacitor 376 to the level detector output374 is relative to the voltage stream 402 provided by the RF detectioncircuit 360 at the level detector input 372, except that any increasedvoltage 412, 422 is held for a duration longer than that of the voltagestream 402 from the RF detection circuit 360. The amount of durationthat any increased voltage is held is strictly a factor of the sizing ofthe at least one capacitor, the sizing of an associated resistor, andthe current drawn by subsequent devices.

Referring now to FIG. 10, the level detector 370 creates the voltagestream 404 where the longer periods of increased voltage 412 (FIG. 9)are more consistent such that there is less voltage decline between theresulting longer periods of increased voltage 414. This voltage stream404 is then output to a non-linear amplifier 380 from a level detectoroutput 374.

Individual components present in one embodiment of the level detector370 are represented in FIG. 7. While most of the components are selfexplanatory to one skilled in the art, it is notable that the leveldetector 370 made in accordance with one embodiment includes two 10 μFcapacitors 376 sufficient to hold a voltage for up to six seconds. Thisamount of time has been found to be sufficient to join message voltages412 (FIG. 9) in the voltage stream 402 (FIG. 9) for the measurementsmade by the microprocessor 310, discussed more fully below. The amountof time duration may be less or more depending on the congruity of themessages typically being sent and the speed of the processor 310.

More generally speaking, the duration needed for the present embodimentis approximately ten times the period of the longer sections ofincreased voltage 410 provided by the premise device. Accordingly, theduration may change depending on the premise devices present. Further,it should be understood that the term approximately is used here inrelation to the “ten times” multiplier because less than ten times maywork well enough if a low voltage threshold (“VIL”) is reducedaccordingly to allow for greater voltage drops between the longersections of increased voltage 410. More than ten times may result in aduration that is too long, there the voltage may not drop soon enoughpast the VIL to properly stop a series. These statements will beunderstood once the VIL and its effect on a series is discussed morefully below. As would be understood by one skilled in the art based onthe present description, the amount of capacitance desired for aparticular amount of duration may be accomplished by one large capacitoror a plurality of smaller capacitors.

Referring back to FIG. 3, the non-linear amplifier 380 is connectedelectrically downstream from the level detector 370 such that the leveldetector output 374 is electrically connected to a non-linear amplifierinput 382 (FIG. 11). The non-linear amplifier 380 compresses the voltagestream 404 provided by the level detector 370 to provide additionalresolution to lower voltages. Specifically, the non-linear amplifier 380provides additional detail to lower voltages without unnecessarilyproviding additional resolution to higher voltages. This is important inthe present embodiment of the upstream bandwidth conditioning devicebecause the microprocessor 310 accepts a voltage stream from thenon-linear amplifier 380 at the non-linear amplifier output 384 (FIG.11) and converts it to a digital value in the range of 0-255. Additionalresolution applied to the entire voltage stream from the level detector370 would require more than 255 digital values, and a linear resolutionof the voltage stream from the level detector 370 may result in poorquality measurements of the upstream bandwidth. Individual componentspresent in one embodiment of the non-linear amplifier 380 arerepresented in FIG. 11. It should be understood that when additionalresolution within the microprocessor 310 is available, the non-linearamplifier 380 may not be required.

The non-linear amplifier 380 is shown in FIG. 11 to include a resistor386 positioned near the non-linear amplifier input 382. This resistor386 allows for the voltage stream 404 from the level detector 370 tobleed off rather than to maintain a particular voltage indefinitely.Accordingly, it should be understood that this resistor 386 may beconsidered to be a part of either the level detector 370 or thenon-linear amplifier 380.

An example of a linearly changing input voltage stream 430 along with anon-linearly changing output voltage stream 440 can be seen in FIG. 12.As shown, at relatively low input voltage levels, the output voltagestream 440 changes significantly more in relation to any changes in theinput voltage stream 430. However, at relatively high voltage levels,the output voltage stream 440 changes significantly less in relation toany changes in the input voltage stream 430.

FIG. 13, represents an exemplary output voltage stream 405 produced inresponse to the voltage stream 404 represented in FIG. 10. As shown, theeffect of the non-linear amplifier 380 is to emphasize details presentin the lower voltages while deemphasizing the higher voltages. Asmentioned above, this effect of the non-linear amplifier 380 helpsprovide additional resolution to the lower voltages for measurementpurposes.

Referring again to FIG. 3, the microprocessor 310 may be electricallyconnected downstream from the non-linear amplifier 380 such that themicroprocessor 310 is connected to the non-linear amplifier output 384.The microprocessor 310 measures the individual voltages from thenon-linear amplifier 380 and may convert these voltages into a digitalscale of 0-255. It should be understood that the present scale of 0-255was chosen in the present embodiment only because of the capabilities ofthe microprocessor 310. Many other scales, including an actual voltagemeasurement may also function depending on the capabilities of themicroprocessor 310. Because of these possible differences in measurementvalue scales, the term “level value” will be used throughout to describethe value assigned to a particular voltage input to the microprocessor310 for further processing. Further, as mentioned above, the non-linearamplifier 380 may not be needed if the microprocessor 310 used includesgreater resolution capacities than the in the present embodiment.

The operation and control of the upstream section 105 will now bedescribed in detail with reference to a flow chart shown in FIG. 14. Asmentioned above, the upstream bandwidth conditioning device 100 mayintentionally attenuate the upstream bandwidth knowing that most premisedevices will automatically increase their output level to counteract theeffect of the any added attenuation. Accordingly, with each amount ofadded attenuation, the signal-to-noise ratio of the upstream bandwidthincreases because the noise is attenuated and the premise device hasincreased its output of desirable frequencies. The limit of thisincrease in signal-to-noise ratio is the amount of increase in thedesirable upstream bandwidth that can be added by the premise device.Accordingly, the level of the upstream bandwidth must be checked andmonitored to ensure that the amount of added attenuation does notcontinually exceed the amount of additional output possible by thepremise device.

Referring now to FIG. 14, the microprocessor 310 works through a seriesof process steps 600 to determine a level value of the desirableupstream bandwidth generated by a premise device. As part of thisdetermination, the microprocessor utilizes two buffers, a Buffer Ø and aBuffer 1.

The Buffer Ø has eight input locations (Ø-7) in the present embodiment.In the process 600, the Buffer Ø input locations, may be referred to intwo separate manners. First, the Buffer Ø input locations may bereferred to specifically as Buffer (Ø, Ø), Buffer (Ø, 1), Buffer (Ø, 2),Buffer (Ø, 3), Buffer (Ø, 4), Buffer (Ø, 5), Buffer (Ø, 6), and Buffer(Ø, 7). Second, the Buffer Ø input locations may be referred to asBuffer (Ø, X), where X is a variable that is increased and reset as partof the process 600. The average of the Buffer Ø input locations isreferred to herein as the current average value (“CAV”).

The Buffer 1 has eight input locations (Ø-7) in the present embodiment.In the process 600, the Buffer 1 input locations may be referred tospecifically as Buffer (1, Ø), Buffer (1, 1), Buffer (1, 2), Buffer (1,3), Buffer (1, 4), Buffer (1, 5), and Buffer (1, 6) and Buffer (1, 7).Further, the Buffer 1 Input Location may be referred to as Buffer (Ø,Y), where Y is a variable that is increased, decreased, and reset aspart of the process 600.

Each of the Buffer Ø and the Buffer 1 may include more or less thaneight input locations. While it has been found that eight input locationworks well for the intended purpose of obtaining a level of the upstreambandwidth, more input locations may provide a smoother level value withless volatility. The additional input locations come at a cost ofadditional time to obtain a level measurement and additional processorconsumption.

Upon a powering on of the upstream bandwidth conditioning device 100,the microprocessor 310 performs an initialization routine, whichincludes steps 602, 604, 606, and 608. According to step 602, the BufferØ input location X is set to Ø, and the Buffer 1 input location Y is setto Ø.

Further according to step 602, the microprocessor 310 starts a setbacktimer, which is set to run for ten minutes in the present embodiment. Aswill become more apparent during the following description, this tenminute timer is intended to release attenuation placed on the upstreambandwidth when there is no activity from a premise device sensed for theten minutes. The term “activity” is used here to describe the presenceof a CLV that is above VIH. The time of ten minutes may be shorter orlonger depending on the experience of users on a particular CATVnetwork. The ten minute time was chosen for the present embodiment inlight of an assumption that most people using the internet, VOIP, and/orSTB/STU will perform at least one function within a ten minute span. Itis assumed that time spans longer than ten minutes typically mean thatno user is currently utilizing the internet, VOIP, and/or STB/STU.

Further according to step 602, the return attenuator 320 (FIG. 3) is setto 4 dB of attenuation. This amount of attenuation is the baseattenuation provided by the present embodiment of the upstream bandwidthconditioning device 100. This base amount of attenuation may beincreased or decreased based on the experience of a particular CATVsystem. This base amount of 4 dB was chosen because it offered someamount of beneficial noise reduction, but it was low enough to notinterfere with any tested premise device, when that premise device wasinitially turned on and was functioning normally.

According to step 604, the microprocessor 310 checks to see whether theBuffer Øinput location X is equal to 8. The purpose of step 604 is todetermine whether Buffer Ø is full. The value of 8 is used, because X isincremented by one after a seed value (discussed below) is placed in thelast buffer location (i.e. Buffer (Ø, 7)). Accordingly, even thoughthere is no location “8,” the value of eight is relevant to the presentdetermination. It should be understood that a value of “7” could also beused if the step of incrementing the value of “X” occurs at a differentlocation in the process 500. If the answer to step 604 is “no,” themicroprocessor 310 moves to step 606. Otherwise, the microprocessor 310moves to step 608.

According to step 606, the microprocessor 310 places a seed value intoBuffer (Ø, X), which in the first instance is Buffer (Ø, Ø). The seedvalue is an empirically derived value that is relatively close to thelevel value anticipated to be found. In other words, the seed value inthe present embodiment is experimentally determined based on actualvalues observed in a particular CATV system. The seed value needs to berelatively close to the initial level value of the upstream bandwidth toallow the upstream bandwidth conditioning device 100 to start astabilization process. After filling Buffer (Ø, X) with the seed value,the microprocessor returns to step 604 to check whether Buffer Ø isfull. This process between steps 604 and 606 continues to fill all ofthe Buffer Ø input locations with the seed value. Once full, themicroprocessor moves to step 608.

According to step 608, the microprocessor 310 is to obtain a CAV of theBuffer Ø, and place that value in Buffer (1, Y), which in this firstinstance is Buffer (1, Ø). The microprocessor resets the Buffer Ø inputlocation X to Ø, but leaves the seed values in the Buffer Ø inputlocations. One skilled in the art would understand that the presentprocess will function normally if the values in Buffer Ø are erased orleft as is to be written over at a later time.

Further in accordance with step 608, a high voltage limit (“VIH”) and alow voltage limit (“VIL”) are calculated based on the CAV value placedinto Buffer (1, Y), which is currently Buffer (1, Ø). Note that thiscould also be worded as calculating VIH and VIL based on the CAV.Regardless, VIH and VIL are calculated values that are used in latersteps to exclude a vast majority of level values that are not near theexpected level values. This exclusion helps to make the present upstreambandwidth conditioning device 100 more stable by avoiding mistaken peakvalue measurements that are far below the expected values. Because bothVIH and VIL are determined after every new CAV is determined, VIH andVIL are allowed to float in the event of a large change in the levelvalues received. In the present instance, VIH is to be approximately 94%of the Buffer (1, Y), and VIL is to be approximately 81% of the Buffer(1, Y). Both VIH and VIL may be other ratios that allow for more or lesslevel values to be included in any peak value determination. The peakvalue determination will be discussed further below, but it may behelpful to explain here that VIH sets a high initial threshold wherelevel values below VIH are excluded from consideration. Similarly, VILis a low secondary threshold where level values are considered until alevel value of a particular series (a series starting when a level valueexceeds VIH) is below VIL. In other words, a series of level values willbe examined for a single peak value, the series beginning with a levelvalue exceeding VIH and ending with a level value falling below VIL.Because the most recent CAV is the seed value of 51, VIH is calculatedto be 48 and VIL is calculated to be 41. These values will, of course,change as the CAV changes after actual level values are obtained. Aftercompletion of the present step, the microprocessor moves to step 610.

In accordance with step 610, the microprocessor 310 obtains a currentlevel value (“CLV”). The CLV is the value of the voltage provided by thenon-linear amplifier 380 (FIG. 3) at the current time. Once a CLV isobtained, the microprocessor proceeds to step 612.

According to step 612, the microprocessor 310 looks to see whether therecently obtained CLV is greater than VIH to start considering a seriesof level values. As mentioned above, if the particular CLV is the firstobtained value (since having a value fall below VIL) that is greaterthan VIH, it is the first of a series. Accordingly, if the CLV is belowVIH, the microprocessor 310 proceeds to step 614 to determine whetherCLV is less than VIL, which if true would stop the series. If the CLV isgreater than VIH, the next step is step 618.

According to step 614, the microprocessor 310 looks to see whether therecently obtained CLV is less than VIL. As mentioned above, all of thelevel values obtained that fall below VIL are eliminated fromconsideration. The process 600 moves to step 616 when the CLV is lessthan VIL. Accordingly, if the CLV is greater than VIL, the next step isback to step 610 to obtain a new CLV to continue the series started byhaving a CLV greater than VIH. It should be understood that any of thesecomparisons to VIH and VIL may be equal to or less/greater than insteadof merely less/greater than. The additional values used or not usedwould not significantly alter the result.

Once the microprocessor 310 proceeds through step 616 a sufficientnumber of times incrementing the Buffer Ø input location X, step 622will be satisfied indicating that the Buffer Øis ready to be averaged.Accordingly, once step 622 is satisfied the microprocessor 310 moves tostep 624.

In accordance with step 624, the microprocessor 310 calculates a CAV,which is the average of Buffer Ø, and sets the Buffer Ø input location Xto Ø. The microprocessor 310 then proceeds to step 626.

In accordance with step 626, the microprocessor determines whether CAVis greater than the value of Buffer (1, Y)+6. To add clarity to thisstep, if Buffer (1, Y) is 51, the microprocessor is determining whetherthe CAV is greater than 51+6, or 57. This value of “6” added to theBuffer (1, Y) value adds stability to the process 600, in that the CAVmust be sufficiently high in order to add additional attenuation in step629. Accordingly, a larger value than “6” may be used to add greaterstability at the risk of reducing accuracy. Similarly, a value less than“6” may be used to add greater accuracy at the risk of reducingstability. The microprocessor 310 moves to step 629 to add attenuationif step 626 is answered in the affirmative. Otherwise, themicroprocessor 310 moves to step 628.

In accordance with step 629, the microprocessor 310 adds an additionalstep of attenuation, which in the present embodiment is 1 dB.Additionally, the microprocessor increments the Buffer 1 input locationY in preparation for placing the CAV into Buffer 1. Afterward, themicroprocessor moves to step 631.

In accordance with step 631, the microprocessor 310 determines whetherthe Buffer 1 input locations are full. Because there are only eightinput locations in Buffer 1, (Ø-7) a value of 8 would indicate that theBuffer 1 is full. The reason for this will become evident below. If theBuffer 1 is full, the next step is step 634. Otherwise, the next is step632.

In accordance with step 632, the CAV is placed in the next open Buffer 1input location, Buffer (1, Y). The process then proceeds to step 636.

If the Buffer 1 were full, the microprocessor 310 would have proceededto step 634 instead of step 632. In accordance with step 634, all if thevalues currently in Buffer 1 are shifted down 1 location such that thevalue originally (i.e., before step 634) in Buffer (1, Ø) is removedfrom Buffer 1. The CAV is then placed in Buffer (1, 7). Further in step634, the Buffer 1 input location Y is set to 7. As with step 632, theprocess 600 proceeds to step 636.

In accordance with 636, the microprocessor 310 calculates a new valuesfor VIH and VIL from Buffer (1, Y), which may be Buffer (1, 7) if step364 was previously accomplished. After step 636, the process 600 returnsto step 610 to obtain a new CLV and the relevant portions of process 600are reiterated.

Referring now back to step 628, the microprocessor 310 determineswhether the CAV is less than the value in Buffer (1, Y)−4. Using a valuefor Buffer (1, Y) of 51, the microprocessor would be determining whetherCAV is less than 51−5, or 47. In this example, the process 600 will moveto step 630. Otherwise, the process 600 will move to step 638, whichwill be discussed later.

In accordance with step 630, the microprocessor determines whether thesetback timer has timed out. If the answer is no, the microprocessor 310proceed to step 646 where the setback timer is reset. Otherwise, themicroprocessor 310 moves to step 642.

In accordance with step 642, the microprocessor 310 looks to see whetherthe Buffer 1 input location Y is greater than or equal to 4. If so, themicroprocessor 310 moves to step 644 where the amount of attenuationapplied by the variable attenuator 320 is reduced by 4, and the Buffer 1input location Y is reduced by 4. A value other than “4” may be used ifmore or less of an attenuation reduction is desired based on time. Thevalue of 4 has been found to be a suitable tradeoff between applyingenough reduction in attenuation to ease any additional loads on thepremise devices and reacting too quickly to the non-use of premisedevices. Afterward, the microprocessor 310 moves to step 646 where thesetback timer is reset.

Referring back to step 648, if Y was not greater than or equal to 5 instep 642, the amount of attenuation applied by the variable attenuator320 will be reduced to the base amount of 4 set in step 602, and theBuffer 1 input location Y will be set to Ø. Afterward, themicroprocessor 310 moves to step 646 where the setback timer is reset.

Referring back to step 638, if the microprocessor determined that Buffer1 input location Y is Ø, the microprocessor moves directly to step 636to calculate a new VIH an VIL. Otherwise, it is apparent that thevariable attenuator 320 may be reduced in step 640 by one step, which inthe present embodiment is 1 dB. Also in step 640, the Buffer 1 inputlocation Y is reduced by one. Afterward, the microprocessor moves tostep 636.

Step 636 is the final step in the process 600 before the process 600 isrestarted, absent the initialization process, at step 610. Themicroprocessor 310 may continuously proceed through process 600 asprocessing time allows.

Referring now back to FIG. 3, the amount of attenuation determined bythe process 600 is added and reduced using a variable attenuator 320,which is controlled by the microprocessor 310. Based on the presentdisclosure, it should be understood by one skilled in the art that thereare a variety of different hardware configurations that would offervariable attenuation. For example, an embodiment of the upstreambandwidth conditioning device 100 could include a fixed attenuator and avariable amplifier, which is connected and controlled by themicroprocessor 310. Other embodiments are envisioned that include both avariable amplifier and a variable attenuator. Further, the variablesignal level adjustment device could also be an automatic gain controlcircuit (“AGC”) and function well in the current device. In other words,it should also be understood that the amount of signal level adjustmentand any incremental amount of additional signal level adjustment can beaccomplished through any of a wide variety of amplification and/orattenuation devices.

In light of the forgoing, the term “variable signal level adjustmentdevice” used herein should be understood to include not only a variableattenuation device, but also circuits containing a variable amplifier,AGC circuits, other variable amplifier/attenuation circuits, and relatedoptical circuits that can be used to reduce the signal strength on theupstream bandwidth.

While the present invention has been particularly shown and describedwith reference to certain exemplary embodiments, it will be understoodby one skilled in the art that various changes in detail may be effectedtherein without departing from the spirit and scope of the invention asdefined by claims that can be supported by the written description anddrawings. Further, where exemplary embodiments are described withreference to a certain number of elements it will be understood that theexemplary embodiments can be practiced utilizing either less than ormore than the certain number of elements.

1. A device for conditioning an upstream bandwidth, the device comprising: a return path extending at least a portion of a distance between a supplier side connector and a user side connector; a coupler connected within the return path, the coupler providing a secondary path; a detection circuit connected electrically downstream the coupler; a level detector connected electrically downstream the detection circuit; a microprocessor connected electrically downstream the level detector, the microprocessor comprising a first buffer and a second buffer; and a variable signal level adjustment device connected within the return path electrically upstream from the coupler, the variable signal level adjustment device being controlled by the microprocessor.
 2. The conditioning device of claim 1 further comprising a non-linear amplifier connected electrically downstream the level detector and electrically upstream the microprocessor.
 3. The conditioning device of claim 1, wherein the first buffer is a series peak buffer comprising values relative to a voltage output of the level detector, and the second buffer is an average buffer comprising at least one average of the values placed in the series peak buffer.
 4. The conditioning device of claim 1 further comprising a high-pass filter connected electrically between the coupler and the RF detection circuit.
 5. The conditioning device of claim 1, wherein the detection circuit comprises an amplifier and a detector, the detector translating a frequency dependent voltage stream into a first time dependent voltage stream.
 6. The conditioning device of claim 5, wherein the detection circuit further comprises a low-pass amplifier connected electrically downstream the detector, the low-pass amplifier amplifying longer duration voltages within the first voltage stream a greater amount than shorter duration voltages.
 7. The conditioning device of claim 1, wherein the level detector comprises at least one diode, at least one resistor, and at least capacitor being connected electrically downstream the at least one diode, the capacitor having a discharge time constant at least ten times greater than a lowest period of increased voltages corresponding to an expected desirable upstream bandwidth.
 8. The conditioning device of claim 3, wherein the series peak buffer is originally filled with a seed value, the seed value being within a range of expected values relative to the voltage output of the non-linear amplifier.
 9. The conditioning device of claim 2, wherein the non-linear amplifier provides relatively less amplification to higher voltages from a voltage stream of the level detector than to lower voltages from the voltage stream of the level detector.
 10. The conditioning device of claim 1, wherein the coupler is connected electrically between a user side diplexer filter and a supplier side diplexer filter.
 11. The conditioning device of claim 1, wherein the microprocessor further comprises a memory location for a high voltage threshold and a low voltage threshold, each of the high voltage threshold and the low voltage threshold being calculated from a value placed in the average buffer.
 12. The conditioning device of claim 1 further comprising a setback timer.
 13. A method of conditioning an upstream bandwidth, the method comprising: converting a frequency dependent voltage stream into a time dependent voltage stream including periods of increased voltage; amplifying and maintaining the periods of increased voltages using a low pass amplifier and a peak detector; recording a peak value from a plurality of voltage series from within the output voltage stream, each series beginning with a measured voltage level exceeding a high voltage threshold and ending with a measured voltage level passing below a low voltage threshold; placing the peak values in a first buffer; periodically calculating a first buffer average; placing the each of the first buffer averages into a second buffer; determining whether the first buffer average is one of above and below a value range, the value range being one of the first buffer averages placed in the second buffer plus (+) an upper variance amount and minus (−) a lower variance; adding an increment of attenuation to the upstream bandwidth when the first buffer is greater than the value range; reducing an increment of attenuation to the upstream bandwidth when the first buffer is less than the value range.
 14. The method of claim 13 further comprising: filling the first buffer and with a seed value prior to placing the peak values in the first buffer, the seed value being a value within an expected range of the peak values.
 15. The method of claim 13 further comprising: calculating each of the high voltage threshold and the low voltage threshold based on the average of the first buffer placed in the second buffer.
 16. The method of claim 13 further comprising: amplifying the periods of increased voltage in a non-linear manner such that lower voltages are increased a greater amount than higher frequencies to create an output voltage stream.
 17. The method of claim 13 further comprising reducing an increment of attenuation to the upstream bandwidth when a predetermined time has elapsed since a completion of at least one of the step of recording a peak value, and the step of calculating a first buffer average. 